1. Field of the Invention
The present invention relates to an autoclave for the sterilisation of medical instruments, for example for dental use. In particular, the invention relates to an improved autoclave, as well as to an equipment and arrangement suitable to shorten the work cycle thereof and which can also be employed in a surgery system for the full treatment of medical instruments.
2. Description of the Related Art
In doctor's surgeries, in particular dental surgeries, the use of small-sized autoclaves to sterilise small manual instruments or dental handpieces is well-known. In this context, it is to be borne in mind that by the term “dental handpieces”, counterangles and turbines are meant, that is, dynamic devices which comprise hollow and/or porous bodies into which various driving members are placed in rotation.
A known exemplary autoclave is disclosed for example in EP 992.247, which is hereby incorporated by reference.
The autoclaves most widely used in doctor's surgeries usually have a sterilisation chamber with a volume in the order of 15-25 liters. The chamber is equipped with suitable racks or baskets for the insertion of small trays or object-holding drawers. The trays—about 4 or 5 thereof—provide an overall bolster capable of simultaneously housing a variety of objects to be sterilised: therefore, all the medical equipment used during the course of a working day or of half a working day, can be sterilised together during unproductive clinical time (for example during lunch break or in the evening). In this way, the temporary unavailability of the instruments and devices in the autoclave—for the time required for completion of the sterilisation cycle, about 40-70 minutes—does not represent a limitation to the availability thereof during the doctor's clinical time.
However, concentrating treatment operations of dental handpieces and turbines—comprising one or more of the washing, maintenance, disinfection, cold sterilization, sterilisation, drying and lubricating processes—into one or two events during the day, means that a large number of these instruments must be available, even bearing in mind the ever growing trend to treat turbines and handpieces after each use on a patient: this implies a large financial investment, considering the high cost of turbines and handpieces, which is certainly unwelcome to the dental doctor.
Therefore, in small surgeries or in special circumstances (for example when sterilisation of a series of instruments between patients is required) the time of unavailability of the instruments being treated in the autoclave represents an undesired constraint.
In order to overcome this drawback, since for example sterilisation must in any case comply with minimum times of exposure to the sterilising agent, an effective way to cut down operation time is to act on evacuation times—which evacuation encompasses alternating steps of positive-pressure and negative-pressure impulses—of the sterilisation chamber, which evacuation occurs repeatedly during the same “fractionated vacuum” sterilisation cycle, and on drying times.
At present only two alternatives to reduce such times have been suggested: one provides to increase the power of the vacuum pump and of the steam generator, whereas the other provides to adopt a smaller-volume sterilisation chamber.
In the former case, however, a high purchasing cost of the components and of the corresponding power consumption is in any case to be borne by the user, even though for most of the working conditions, longer sterilisation times are tolerable.
In the latter case, instead, the autoclave is offered on the market with a sterilisation chamber which is remarkably smaller than standard ones (for example the 5.5-liter Millennium Bi model manufactured by Mocom, or the 5-liter 13-B or 14-B Vacuquick® model manufactured by Melag) and at a slightly lower price, but the drawback lies in the fact that, in order to manage heavier-than-scheduled workloads, the user is forced to run the sterilisation process very frequently, with a particularly poor power yield.
Both these solutions consequently have drawbacks, but, most importantly, they do not allow versatile and efficient utilisation of the autoclave to manage both light and medium-heavy workloads.
Moreover, additional problems exist with the handling of dental handpieces. Handpieces in fact also require maintenance, such as deep cleaning, lubrication and drying. To carry out these additional operations, the market currently offers various specific appliances (see, for example, Assistina™ manufactured by W&H, Care3™ by Nsk Nakanishi Inc., QuattroCare™ by Kavo), capable of performing cleaning, lubrication and drying quickly and effectively. However, they imply additional costs and require room in the dentist's surgery. Besides, the instrument always requires manual transfer from the maintenance appliance to the autoclave and viceversa—possibly after being sealed in a blister pack—which does not contribute to a fully sterile cleaning cycle.
On the other hand, more complex appliances (see, for example, DACUniversal™ by Nitram) also exist, which are capable of performing a full treatment cycle (i.e. comprising cleaning, lubrication and sterilisation). However, these appliances are currently rather complex and bulky, since they are designed to treat multiple instruments at the same time (for example six turbines), and they still have some technical problems, such as humidity persistence in the handpieces (which negatively affect storage), as well as long cooling down times, which keep the instruments from being available to clinicians within a short period of time. Finally, it must be noted that at the end of the treatment the instruments still need to be manually removed, thereby affecting sterility thereof. Basically, these devices are capable of performing treatments of multiple instruments only for immediate use thereof, with no opportunity for storage (conservation) and/or transportation of such instruments.